Structure-Based Design of Novel Alkynyl Thio-Benzoxazepinone Receptor-Interacting Protein Kinase‑1 Inhibitors: Extending the Chemical Space from the Allosteric to ATP Binding Pockets

Systemic inflammatory response syndrome (SIRS), characterized
by
severe systemic inflammation, represents a major cause of health loss,
potentially leading to multiple organ failure, shock, and death. Exploring
potent RIPK1 inhibitors is an effective therapeutic strategy for SIRS.
Recently, we described thio-benzoxazepinones as novel RIPK1 inhibitors
and confirmed their anti-inflammatory activity. Herein, we further
synthesized novel thio-benzoxazepinones by introducing substitutions
on the benzene ring by an alkynyl bridge in order to extend the chemical
space from the RIPK1 allosteric to ATP binding pockets. The in vitro
cell and kinase assays found that compounds 2 and 29 showed highly potent activity against necroptosis (EC50 = 3.7 and 3.2 nM) and high RIPK1 inhibitory activity (Kd = 9.7 and 70 nM). Prominently, these two analogues
possessed better in vivo anti-inflammatory effects than the clinical
candidate GSK′772 and effectively blocked hypothermia and deaths
in a TNFα-induced SIRS model.